Appliance for casting dental gold inlays.



V* MACDGNALD.

APQLIANGB POR GAMING DENTAL GOLD INLAYS.

`Air.LIC)A'..`I01\I 'FILED AUG.18,1908.

Patented Nov. l0, w08,

Dosen?, rama.; L Rt NoiiQQSAQQf when Behit known K University yof Pennsyl- .y C'XQJSQ Edinburgh ya subjecty of the King oiGreat Britain and Ireland, re-

or mold can be played upon by the blow pipev until the instant that an asbestos padded cap suddenly -falls or descends upon it and so forces the gold into the cavity of mold in the investment material. Said sudden force or pressure is obtained by the upper asbestos cap piece being supported on a drop head at a distance immediately7 above the mold or investment ring in such a manner-that it can be instantly released and dropped rapidly down from such height onto the molten gold in the cone ofi-the investment ring and thus the gold is forced (while intensely heated) into the cavity therein with the result that a perfect cast of the mold is obtained. The instantaneous and rapid drop of the asbestos padded cap being accelerated by foot pressure imparted through the medium of a treadle or stirrup, thus leaving the operators left hand free, while his right hand is ap- 'plying the blowpipe or flame, and hence the casting of the gold inlay is effected in a simpler and more eiiicient manner than is done with the present known appliances.

' The casting appliance will now be fully described aided by a reierence to the accompanying sheet of drawings in which.-v

Figure l shows it by a front View, and Fig. 2 by a side sectional View, while Fig. 3 shows theu stirrup 'for use in place of a treadle, and Fig. 4 is a modified construction of the drop head.

In the drawings A is a cross or drop' head having the recessed asbestos cap either formed upon or secured to it and within such cap is the asbestos illing a. Said drop head is secured to the upper ends of two'vertical 4sliding rods B whichv pass through guide bushes B1L fitted into a bench or table C, while the lower ends of said rods are'connected together by a bow B2 at the center of which is the bearing for the upper end of a tenerne XenonL in, orfiviniisooaun, vinrent-IA, nostri/ilaria] f that I, viLENTiNE MAC,

withdrawal of the wire.`

APLIANCE Fon oasi-DING DnNTaLeoL'D INLars.

y connecting rod D the lowerend of which is attached to a foot lever or treadle E which is fulcri med in a 'suitably arranged bracket E1, ori, i1 desired, a 'stirrup may be carried at lcwe end of said connecting rod and thus the treadle be dispensed with. F is the mold or impression ring seated on a thick sheet of asbestos F1 lying on a plateF2'on the table or bench C.`

G is a light rod bracket secured to table C', and having a hook 4at its upper end upon which to suspend the drop head until just ,prior to its being released to drop andforce 'the molten gold into the mold or -in place of said bracket a coiled spring H secured between the underside of bench and the top of connecting rod or strap `-may be employed it ICE'.

being just strong enough to hold lthe cross f headand guide rods up.. v

The operation of casting with the appliance is as follows:-Having taken the wax impression in the usual manner and shaped it for the future filling ,it is lifted from the cavity in tooth and a short piece of Wire labout 17 gage (Brown and Sharpe gage plate) for a medium size filling is taken and slightlywarmed at one end and gently attached to the outer surface of the wax impression without distorting it. The wax and Wire are then placed in the. metal impression ring and invested with the requisite molding substance the wire being left to project y through the investment so that it' can be withdrawn. when the latter sets. The mold ring is then heated gradually tov burn out thevestment or mold is nowplaced in the casting appliance after the dro head and side bars are raised to the requisite height for the drop, the head being held up vby a weak spring bracket attached to the bench'aside of the side bars. The investment ringer moldis now placed in .position 'and thoroughly heated, the gold ingot being placed in position over the hole through its top surface and the blow pipe is brought into ac! tion, the left foot meanwhile being kept in position ready to apply the necessary force to the treadle or stirrup to bring the drop head down upon the molten gold ingot in the mold Withsuficient force to vdrive the molten gold into the cavity Withip the intwo vertical .vestment.v The flame. should be kept goin strongly until the drop cap has passe through it and so shut it oif from the guldat the latest possiblel moment. The drop cap Vshould be brought into action suddenly and with considerable force and such' forceas is necessary is readily applied by the foot method. The investment ring or mold is now removed and on cooling the inlay is re.-

vmoved. andnished oli'l in the usual manner. Having 110W described my invention what I claim as new and desire to' secure by Let.

` y my hand in'presence of two subscribing'witters Patent is v. l

1. An improved appliance for casting den- .tal gold inlays consistlng of a drop head furnished with the asbestos cap'and 4carried b ide rods Which-'pass throng guide bushes 1n a-bench or table under which trea le whereby the force of the'falling cap can be accelerated, substantially as 'described.

2. An appliance for casting dental gold moving said rods, means for normally holding 'the drop head in raised position and a mold. l

In testimony'whereof I have hereunto set nesaes-h VALENTINE' MACDONALD. 'Witnesses: 1

. 1. BEDLING'roN .BoDYcoMB, I CHARLES HACKETT. f

the uide rods are connected to a stirrulor' `rop 

